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Seasonal Inhomogeneity of Soot Particles over the Central Indo-Gangetic Plains,India:Influence of Meteorology

Journal of Meteorological Research 2015年第6期29卷 935-949页

作者： SINGH B.P. TIWARI S. HOPkE Philip k. SINGH R.S. BISHT D.S. srivastava a.k. SINGH R.k. DUMkA U.C. SINGH a.k. RAI B.N. srivastava Manoj k. Department of Geophysics Banaras Hindu University Indian Institute of Tropical Meteorology(New Delhi Branch) Cla.k.on University Department of Chemical Engineering Banaras Hindu University Aryabhatta Research Institute of Observational Sciences Department of Physics Banaras Hindu University

Bla.k.carbon（BC） particles play a unique and important role in earth’s climate *** was measured（in-situ） in the central part of the Indo-Gangetic Plains（IGP） at Varanasi,which is a highly populated and polluted region due to its topography and extensive emission *** annual mean BC mass concentration was 8.92 ± 7.0 μg m-3,with 34%of samples exceeding the average ***,BC was highest during the post-monsoon and winter periods（approximately 18 μg m-3） and lower in the premonsoon/monsoon seasons（approximately 6 μg m-3）.The highest frequency（approximately 46%） observed for BC mass was in the interval from 5 to 10 μg ***,during the post-monsoon season,the most common values（approximately 23%） were between 20 and 25 μg *** nighttime concentrations of BC were approximately twice as much as the daytime values because of lower boundary layer heights at *** Angstrom exponent was significantly positively correlated（0.55） with ground-level BC concentrations,indicating the impact of BC on the columnar aerosol *** estimated mean absorption Angstrom exponent was 1.02 ± 0.08 μg m-3,indicating that the major source of BC was from fossil fuel *** negative correlations between BC mass and meteorological parameters indicate a pronounced effect of atmospheric dynamics on the BC mass in this *** highest mean BC mass concentration（18.1 ± 6.9 μg m-3） as a function of wind speed was under calm wind conditions（38%of the time）.

关键词： bla.k.carbon Indo-Gangetic Plains absorption Angstr(o|¨)m exponent biomass fossil fuel

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Synthesis and enhanced photoluminescence properties of red emitting divalent ion(Ca^(2+))doped Eu:Y_(2)O_(3)nanophosphors for optoelectronic applications

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Journal of Rare Earths 2022年第8期40卷 1187-1198页

作者： Arpita Dwivedi Monika srivastava a.k.r Dwivedi Amit srivastava Anurag Mishra S.k.srivastava Department of Physics Institute of ScienceBanaras Hindu University(BHU)Varanasi221005India School of Materials Science and Technology Indian Institute of Technology(BHU)Varanasi221005India Department of Mining Engineering Indian Institute of Technology(BHU)Varanasi221005India Department of Physics TDPG College VBS Purvanchal UniversityJaunpur222001India

This work presents the synthesis of Y_(2)O_(3):Eu^(3+),χCa^(2+)(χ=0 mol%,1 mol%,3 mol%,5 mol%,7 mol%,9 mol%,11 mol%)nanophosphors with enhanced photoluminescence properties through a facile solution combustion method for optoelectronic,display,and lighting *** X-ray diffraction(XRD)patterns of the proposed nanophosphor reveal its structural properties and crystalline *** transmission electron microscope(TEM)results confirm the change in the shape of the particle and aggregation of particles after co-doping with Ca^(2+).Fourier transform infrared spectroscopy(FTIR)and Raman vibrations also confirm the presence of Y-O vibration and subsequently explain the crystalline nature,structural properties,and purity of the *** the synthesized nanophosphors samples emit intense red emission at 613 nm(~5D_(0)→~7 F_(2))under excitation with 235,394 and 466 nm wavelengths of Eu^(3+)*** photoluminescence(PL)emission spectra excited with 235 nm illustrate the highest emission peak with two other emission peaks excited with 466 and 394 nm that is 1.4 times higher than 466 nm and 1.9 times enhanced by 394 nm wavelength,*** emission intensity of Y_(2)O_(3):Eu^(3+),χCa^(2+)(5 mol%)is increased 8-fold as compared to Eu:Y_(2)O_(3).Doping with Ca^(2+)ions enhances the emission intensity of Eu:Y_(2)O_(3)nanopho sphors due to an increase in energy transfer in Ca^(2+)→Eu^(3+)through asymmetry in the crystal field and by introduction of radiative defect centers through oxygen vacancies in the yttria *** is also observed that the optical band gap and the lifetime of the~5D_(0)level of Eu^(3+)ions in Y_(2)O_(3):Eu^(3+),xCa^(2+)nanophosphor sample gets changed with a doping conce ntration of Ca^(2+)*** also reveals high thermal stability and quantum yield as estimating activation energy of 0.25 eV and 81%,***,CCT,and color purity values(>98%)show an improved red-emitting nanophosphor in the warm region of light,which m

关键词： Red emission Photoluminescence(PL) Y_(2)O_(3):Eu^(3+),xCa^(2+) Rare earths Nanophosphors LEDs

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Ce-Co-doped BiFeO_3 multiferroic for optoelectronic and photovoltaic applications

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Chinese Physics B 2017年第11期26卷 383-388页

作者： Jyoti Sharma Deepak Basandrai a.k.srivastava Department of Physics Lovely Professional University

The Ce-Co-doped BiFeO3 multiferroic, Bi（1-x）Ce）xFe（1-x）CoxO3（x = 0.00, 0.01, 0.03, and 0.05）, has been prepared by a sol-gel auto-combustion method and analyzed through Raman spectroscopy, photoluminescence, and UV-visible spectroscopy. We have observed an anomalous intensity of the second-order Raman mode at - 1260 cm^-1 in pure BFO and suppressed intensity in doped samples, which indicates the presence of spin two-phonon coupling in these *** photoluminescence spectra show reduction in the intensity of emission with the increasing dopant concentration, which indicates the high charge separation efficiency. A sharp absorption with three charge transfer（C-T） and two d-d transitions are shown by UV-visible spectra in the visible region. The band gap of BiFeO3（BFO） is decreasing with increasing dopant concentrations and the materials are suitable for photovoltaic applications.

关键词： Raman and UV-visible spectroscopy photoluminescence and photo-voltaic applications

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Tribological behaviour of C/C-SiC composites-A review

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Journal of Advanced Ceramics 2016年第1期5卷 1-12页

作者： Parshant kUMAR V.k.srivastava Department of Mechanical Engineering Indian Institute of Technology(BHU) Varanasi-221005 India

Ceramic matrix composites made of carbon fibres and carbon matrix (C/C) are generally used for aircraft structures and brake discs due to their low density, and good thermal, mechanical, and tribological properties. Silicon carbide (SiC) can be introduced to the matrix to improve the performance of C/C composites, because it increases the hardness and thermal stability, and decreases the chemical reactivity, which leads to the improvement of tribological properties of C/C composites. Thus carbon-carbon silicon carbide (C/C-SiC) composites can be used at high temperature for the application of brake discs, friction clutches, etc. C/C-SiC composites are fabricated by three different methods: (i) chemical vapour infiltration (CVI), (ii) polymer infiltration and pyrolysis (PIP), and (iii) liquid silicon infiltration (LSI), among which LSI method is widely used for the fabrication of C/C-SiC composites due to higher mechanical and thermal properties.

关键词： carbon-carbon (C/C) composites coefficient of friction wear

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Implications of multipurpose tree leaf application on wheat productivity in dry tropics

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Journal of Forestry Research 2013年第4期24卷 777-782页

作者： Rajani srivastava k.P.Singh Department of Botany Banaras Hindu University

Leaves of multipurpose tree species （those providing more than one function or product of human use） can serve as sources of fer- tilizer for nutrient supply, especially nitrogen （N）. In this study chopped leaves of tropical tree species （5 N-fixing species, 5 non-N-fixing species and combinations of 5 N-fixing with a non-N-fixing species） were in- corporated in soil to evaluate its effects on wheat biological productivity （including grain yield, GyIELD） under dryland conditions. High quality leaves of N-fixing tree species （e.g. Dalbergia sissoo, Cassia fistula and Prosopis cineraria） had lower carbon/nitrogen （C/N）, lignin/nitrogen （L^o/N）, polyphenol/nitrogen （PPt/N） and lignin＋polyphenol /nitrogen （L~＋PpL/N） ratios than low quality leaves of non-N-fixing species. Com- bination treatments had intermediate values of different parameters, Application of high quality leaves caused greater increases in wheat productivity and yield than other species.

关键词： multipurpose tree leaves chemical quality index grain yield,N-fixing species non-N fixing species Dryland agriculture

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Data-driven failure diagnosis in transmission protection system with multiple events and data anomalies

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Journal of Modern Power Systems and Clean Energy 2019年第4期7卷 767-778页

作者： Amir GHOLAMI Anurag k.srivastava Shikhar PANDEY Washington State University PullmanUSA

To guarantee a reliable power supply,the expected operation of all the components in the power system is *** protection system is primarily responsible of isolating the faulty section from the healthy part for the *** in protection devices can result in multiple conflicting alarms at the power grid operation center and complex event analysis to manually find the root cause of the observed system *** not handled in time,it may lead to the propagation of the faults/failures to the adjacent transmission lines and *** availability of the synchronized measurements from phasor measurement units(PMUs),real-time system monitoring and automated failure diagnosis are *** multiple adverse events and possible data anomalies,the complexity of the problem will be *** this paper,a PMUbased algorithm is presented and discussed to detect the root cause of the failure in transmission protection system based on the observed state,*** line tripping andbreaker *** failure diagnosis algorithm is further enhanced to come up with the fully functional version of the failure diagnosis tool,which is tailored for the cases in which the PMU anomalies are *** the developed algorithm,the validity of the PMU data is ***,such causes as communication errors or cyber-atta.k. might lead to the PMU data *** issue is welladdressed in this paper and some major types of anomaly detection methods suitable for PMU data are *** show that the ensemble approach has some distinct advantages in data anomaly detection compared to the previously used standalone ***,the enhanced failure diagnosis method is developed to clean the inaccurate data in case of the anomaly in measured voltage ***,both original and enhanced versions of the tool are tested on 96-bus test system using the real-time OPAL-RT *** results show the accuracy of the enhanced tool and

关键词： Failure diagnosis Transmission protection system Protection mis-operation Phasor measurement unit(PMU) Data anomaly and cleaning Ensemble method

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Synthesis and Biological Study of Some 4-oxo-Thiazolidine Derivatives of 2-Aminothiazole

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Chinese Journal of Chemistry 2011年第5期29卷 1001-1010页

作者： Samadhiya Pushkal Sharma Ritu srivastava Santosh k. srivastava Savitri D. Synthetic Organic Chemistry Laboratory Department of Chemistry Dr. H.S. Gour University (A Central University) Sagar M.P. 470003 India

Conventional and microwave assisted synthesis of new series of N-[2-{2-（substituted phenyl）-4-oxo- 5-（substituted benzylidene）-1,3-thiazolidine}-iminoethyl]-2-aminothiazole 5a-Sin have been developed. The cycloaddition reaction of thioglycolic acid with N-{2-（substituted benzylidenehydrazino）-ethyl}-2-aminothiazole 3a--3m in the presence of anhydrous ZnC12 afforded new heterocyclic compounds N-[2-{2-（substituted phenyl）- 4-oxo-l,3-thiazolidine}-iminoethyl]-2-aminothiazole 4a---4m. The later product on treatment with several selected substituted aromatic aldehydes in the presence of C2HsONa undergoes knoevenagel reaction to yield 5a--Sin. The structures of compounds 1, 2, 3a--3m, 4a---4m and 5a--Sm were confirmed by IR, IH NMR, 13C NMR, FAB-Mass and chemical analysis. All above compounds were screened for their antimicrobial activities against some selected bacteria and fungi and antituberculosis study against M. tuberculosis.

关键词： conventional microwave synthesis 2-aminothiazole 4-oxo-thiazolidine antimicrobial antitubercular

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Synthesis of N1-3-{（4-Substituted aryl-3-chloro-2-oxo- azetidine）-iminocarbamyl}-propyl-6-nitroindazole Derivatives and Their Biological Significance

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Chinese Journal of Chemistry 2011年第8期29卷 1745-1752页

作者： Samadhiya, Pushkal Sharma, Ritu srivastava, Santosh k. srivastava, Savitri D. Synthetic Organic Chemistry Laboratory Department of Chemistry Dr. H. S. Gour University (A Central Univer- sity) Sagar M.P. 470003 India

Synthesis of N1-3-{（4-substitute daryl-3-chloro-2-oxo-azetidine）-iminocarbamyl}-propyl-6-nitroindazole 4a-- 4s was conducted by a conventional method. All the compounds were synthesized and characterized by IR, 1H NMR, 13C NMR, FAB-Mass techniques and chemical methods. All the final synthesized compounds were evaluated for their antimicrobial activity and antitubercular activity with MIC values against some selected microorganisms.

关键词： synthesis 6-nitroindazole 2-azetidinone biological activity

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A near infrared optical reflector using one-dimensional photonic crystal structure containing chalcogenide glasses

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Optoelectronics Letters 2010年第6期6卷 406-411页

作者： Sanjeev k.srivastava S k Awasthi S k srivastava S.P.Ojha Department of Physics Amity Institute of Applied SciencesAmity University Department of Physics Jaypee Institute of Information TechnologyDeemed University Department of Physics Mahila Maha VidyalayBanaras Hindu University Department of Applied Physics Institute of TechnologyBanaras Hindu University

The reflectivity of one-dimensional chalcogenide photonic crystal(CGPC) structure with the first order reflection band in near infrared(NIR) region is theoretically ***-Se and Ge-S chalcogenide glasses are used as high and low refractive index layers respectively,because these materials have zero absorption in NIR *** transfer matrix method(TMM) is employed to calculate the reflective spectra of the proposed *** theoretical results of reflective spectra of bulk chalcogenide materials with the composition of Sb40Se60 and Ge30S70 for 4,8,12 and 15 layers and thicknesses of 117 nm and 183 nm respectively,at normal incidence,are close agreement with the experimental ***,by increasing the number of layers of Sb40Se60 and Ge30S70,the reflection bands can be enhanced in the wider range of the NIR region for the polarization at different angles and thus the broadband omnidirectional reflector can be designed.

关键词：一维光子晶体晶体结构硫系玻璃近红外光反射镜红外区域反射光谱计算结果

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Electrochemical Impedance Analysis of Biofunctionalized Conducting Polymer-Modified Graphene-CNTs Nanocomposite for Protein Detection

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Nano-Micro Letters 2017年第1期9卷 104-112页

作者： Shobhita Singal Avanish k.srivastava Rajesh CSIR-National Physical Laboratory Dr.K.S.Krishnan RoadNew Delhi 110012India Academy of Scientific and Innovative Research(AcSIR) CSIR-National Physical LaboratoryDr.K.S.Krishnan RoadNew Delhi 110012India

We report an electrodeposited poly(pyrrole-co-pyrrolepropylic acid) copolymer modified electroactive graphene-carbon nanotubes composite deposited on a glassy carbon electrode to detect the protein antigen(cTnI). The copolymer provides pendant carboxyl groups for the site-specific covalent immobilization of protein antibody, antitroponin I. The hybrid nanocomposite was used as a transducer for biointerfacial impedance sensing for cTnI *** results show that the hybrid exhibits a pseudo capacitive behaviour with a maximum phase angle of 49° near 1 Hz,which is due to the inhomogeneous and porous structure of the hybrid composition. The constant phase element of copolymer is 0.61(n = 0.61), whereas, it is 0.88(n = 0.88) for the hybrid composites, indicating a comparatively homogeneous microstructure after biomolecular functionalization. The transducer shows a linear change in charge transfer characteristic(R_(et)) on cTnI immunoreaction for spiked human serum in the concentration range of 1.0 pg mL^(-1)–10.0 ng mL^(-1). The sensitivity of the transducer is 167.8 ± 14.2 Ω cm^2 per decade, and it also exhibits high specificity and good reproducibility.

关键词： Conducting polymer Graphene Carbon nanotube Hybrid Transducer Protein antigen cTnI Electrochemical impedance

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